Init dataset/layer config for seal tag data pulled from ADC

[trey-stafford]

Description

This PR adds a vector dataset giving the locations of seal tag measurements (water temp, salinity, depth, etc) from the ADC for demonstration purposes. This layer is relatively small and "easy" to transform into a QGreenland-ready dataset (csv w/ latitude and longitude columns -> Geopackage via ogr2ogr) and may be a good test-case for QGreenland-Net work.

Command to generate an (unzipped, -Z option) QGreenland package with the background layer and this new layer:

$ ./scripts/cli.sh run -Z --include="background" --include "seal_tag_measurements"

---

Note that there might be one issue with the dataset that isn't so "easy" to deal with: there appear to be rows that have no "Cruise", "Station", "Type", or "Date" values. These rows follow in chunks after rows that do have those values. I'm wondering if the values are "constant" until the next row w/ updated values for those attrs. E.g.,:

"Cruise","Station","Type","Date","Longitude","Latitude","depth_from_surface","Pressure","Temperature","Salinity","Fluorescence","Oxygen"
...
"ct71-01-10",1,"B","2010-08-31 12:00",-43.3587,60.0247,NA,40,-0.475,32.8837,999,999
"",NA,"","",NA,NA,NA,50,-0.6026,32.9236,999,999
"",NA,"","",NA,NA,NA,60,-0.6664,32.9769,999,999
"",NA,"","",NA,NA,NA,80,-0.743,33.1467,999,999
"",NA,"","",NA,NA,NA,100,-0.743,33.2,999,999
"",NA,"","",NA,NA,NA,113,-0.743,33.2,999,999
"ct71-01-10",2,"B","2010-08-31 17:00",-43.2995,60.0515,0,2,5.258,29.966,999,999
"",NA,"","",NA,NA,NA,10,5.1107,30.0879,999,999
"",NA,"","",NA,NA,NA,12,4.9477,30.1562,999,999
"",NA,"","",NA,NA,NA,14,4.8846,30.2049,999,999
"",NA,"","",NA,NA,NA,16,4.7479,30.3,999,999
...

If we end up wanting to actually include this data in QGreenland, we'll want to investigate more and fix if needed.

Checklist

If an item on this list is done or not needed, check it with [x] or click the checkbox.

• [ ] The PR description links to issues that it resolves with closes #{issue_number}
• [x] Config lockfile updated (inv config.export > qgreenland/config/cfg-lock.json)
• [ ] Environment lockfile updated if needed (conda-lock)
• [ ] Version bumped if needed (bumpversion (major|minor|patch|prerelease|build))
• [ ] CHANGELOG.md updated (for user-facing changes)
• [ ] Documentation updated if needed
• [ ] New unit tests if needed